This invention relates to a retreading system for curing radial constructed tires. In this system of retreading, the curing envelope is sealed by expanding a rubber ring in the radial direction causing the seal to take place in the radial direction on the axial bead surface. This sealing system permits easy positioning of the bead seal ring unit because the diameter is smaller than the diameter of the tire's bead member when it is in the relaxed position, and in the expanded position there is a positive sealing action between the ring unit and the bead member of the tire securely sealing the curing envelope.
It is conventional in retreading to seal the curing envelope between the sidewall or side surface of the tire. Examples of sealing systems used in retreading systems are described in detail in U.S. Pat. Nos. 2,966,936, 3,236,709, 3,802,978, 3,884,740, 3,895,985, 3,966,535, 4,129,474, 4,175,991, 4,242,169, 4,274,897, and 4,309,234. These references disclose various concepts of sealing the curing envelope bewteen a mechanical structure and the sidewall or side surface of the tire casing.
One known invention attempting to seal in the radial direction was disclosed in United Kingdom Application No. GB2,032,858A is the closest known reference in regards to the present invention.